The present invention relates to access control systems, and more particularly to an electronic door lock used in an access control system.
Some access control systems include solenoid type locks that are arranged in either a fail safe or a fail secure setting that occurs in the event of a power failure. For example, if the lock is configured with a fail safe setting, the lock will unlock or remain unlocked to allow access to an access controlled area when the lock loses power. If the lock is configured with a fail secure setting, the lock will lock or remain locked to prevent access to an access controlled area when the lock loses power.
Solenoid type locks with a fail safe setting have a different mechanical design than solenoid type locks with a fail secure setting. Thus, a user must choose one option (e.g., fail safe or fail secure) and cannot reconfigure the lock to perform the other option (e.g., fail secure or fail safe). The mechanical designs for the fail safe and fail secure solenoid type locks are similar except the solenoid is oriented in a different direction in each design. Thus, in the event of a power failure, the solenoid will cause the latch of the locking mechanism to retract (e.g., fail safe) or extend (e.g., fail secure) depending on the orientation of the solenoid.
Solenoid type locks have many disadvantages. The solenoids are large and heavy, adding size and weight to the lock. Solenoids are also subject to attack with the use of magnets. For example, if an intruder uses a strong enough magnet, the intruder can overcome the magnetic force of the solenoid and drive the latch to the desired position to unlock the lock and gain access to the access controlled area.